Juve suffered a 5-1 humiliation to the Serie A leaders.
Allegri later said: "First of all, we must congratulate Napoli on their performance. We were a little low on energy when dealing with all the goals, were too deep for the opening 20 minutes and then conceded the second goal just as we were pushing forward.
“We had chances and the feeling we could score, but this is football and every time Napoli had a shot, it could've been a goal. You just need to see the third goal when it was a corner that wasn't cut out.
“There's a long road ahead and many points up for grabs, so we have to get working and look forward."
Allegri added, “This was a deserved defeat, because we went into the game with less energy. The situations we conceded were also fairly easy to read and predict, but sometimes luck is on your side and sometimes it isn't. We tried to turn it around towards half-time, but Napoli fully deserved it.
“That doesn't mean we should let our heads drop, because we can be proud of the eight consecutive victories and need to get back on track in Serie A and the Coppa Italia."
